a good freind has an 89 f-150 302/aod/1356. ive had it sitting out back for a few years, so when he needed a ride recently, we pulled it in the shop and fixed the few things that we knew were wrong with it. he has been driving it for a week or two now, and when you let off the throttle to slow down for a corner or stop sign, the trans will start clicking away, like a ratchet almost. it sounds like something is free-wheeling in the trans. it is deffinitely not good sounding, but i dont know much about these transmissions. the sound will go away if the throttle is applied enough to catch the trans up the the traveling speed, but continue decelerating.

what may be making the noise, and is it fixable? should he just run it till it quits?